Learn Dutch: Hij is een trouwe partner. - He is a faithful partner.

In Dutch, adjectives usually get an -e ending when they come before a noun. Because partner is a de-word (de partner), the adjective takes the -e even after een (a). You only leave the -e off when you have een followed by a het-word.

Does trouwe always mean "faithful" in a romantic sense?

Not necessarily! While it translates to "faithful" here, trouw is also the standard word for "loyal". You can use it to describe a loyal friend (een trouwe vriend) or even a loyal dog (een trouwe hond).

Is the word partner used exactly the same way as in English?

Yes, partner is a loanword from English and means the same thing. Because it refers to a person, it is a de-word (de partner). The pronunciation is very similar to English, but usually spoken with a more distinct Dutch "r" sound.